1. Field of the Invention
This invention concerns striking instruments such as hammers and more particularly hammer constructions in which the handle and head are constructed separately and are assembled together.
2. Background Discussion
Hammers and other striking tools such as axes, mattocks, etc. have long been constructed by joining wooden handles to steel heads by means of an opening formed within the hammer head received in one end of the handle, with a wedge driven into the terminal end of the handle to create a tight engagement of the handle within the head opening. This construction, while adequate for relatively light duty hammers, does have the disadvantage that the absorption of moisture on the wood handle creates a tendency for the hammer head to become loosened requiring resetting of the wedges or replacement of the handle. In addition, in heavy-duty commercial use of such hammers, such as in manufacturing operations or such commercial enterprises as body repair and tire installation shops, the strength requirements are such that there is a high incidence of failure of the wood handles by breakage and the life of such hammers before they become loosened or break is uneconomically short such that replacement of hammers is a significant expense item in such operations.
In addition, these hammers create safety hazards by the head coming loose while in use such as to sometimes result in the hammer head being completely dislodged and thrown from the handle as the hammer is being wielded.
Another approach has involved the use of relatively lightweight handle material such as of a fiberglass handle joined to the metal hammer head, as by the use of adapters which secure the fiberglass handle to the head by tapered sleeves cooperating with the formed opening in the hammer head. The taper direction is such as to resist the tendency for the hammer head to be dislodged outwardly from the handle during use. Such an approach is described in U.S. Pat. Nos. 3,753,602 and 3,819,288. However, in the aforementioned heavy-use situation, the material used for the adapters, i.e., plastic resinous material, tends to become worn relatively quickly which allows loosening of the hammer head and a high incidence of failure after only relatively short periods of use.
While an all-metal or one-piece hammer construction would eliminate such problems, the cost of constructing a one-piece all-metal hammer would be excessive since the entire hammer must then be drop forged due to the fact that all portions of the hammer must then be of the same strength as the head. Since there is a large number of different head configurations, drop forge tooling wouuld be required for each. In addition, the weight of the hammer would be adversely affected since the handle portion would then be of necessity formed of steel such as to render the hammer relatively unwieldy.
While other hammer construction methods have been utilized, they generally have suffered from the drawbacks described above, i.e., either are not sufficiently durable under heavy-duty use to result in an uneconomically short useful lives and the incidence of hazardous failures, or are of overly costly construction.
It is accordingly an object of the present invention to provide a hammer construction which is extremely durable and which reduces the incidence of failure by separation of the hammer head and handle portion to an absolute minimum.
It is yet another object of the present invention to provide such a hammer construction which may be manufactured at a relatively modest cost without the necessity of heavy capital investment in forging dies, etc., and yet which may be adapted to hammers having a variety of head configurations.
It is yet another object of the present invention to provide such a hammer construction in which the nonstriking portions of the hammer are relatively light in weight while being of relatively great strength and durability.
It is still a further object of the present invention to provide such a hammer construction which is of a relatively simple design and easily manufactured.